


testing the limits

by Sin_Cognito



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Alternate Universe - Underswap, Edge Is a Dick, M/M, Smut, Underfell Papyrus, Underfell Sans, Underswap Papyrus, Underswap Sans, bad edge, honeymustard - Freeform, stretch needs a hug
Language: English
Status: Completed
Published: 2018-01-02
Updated: 2018-01-02
Packaged: 2019-02-27 13:09:59
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,856
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13248909
Author URL: https://archiveofourown.org/users/Sin_Cognito/pseuds/Sin_Cognito
Summary: It seems Stretch has had enough with Edge. Luckily, Red is there to comfort his boyfriend.





	testing the limits

**Author's Note:**

> From a tumblr request :  
> so, can u write something about honeymustard? (i saw the ask about it and now i’m kinda curious?(that’s not the right word)) idk, maybe with stretch kinda depressed and red worried or something like that. it’s ok if you can’t or don’t want to

_"DON'T SMOKE NEXT TO ME. IT DISGUSTS ME."_

 

_"ARE YOU SO STUPID YOU DON'T EVEN UNDERSTAND THAT ?"_

 

_"STOP BEING SO USELESS AND DO THE FUCKING LAUNDRY."_

 

_"HA ! YOU WANT ME TO HELP YOU COOK ? IN YOUR DREAMS ASHTRAY !"_

 

* * *

 

 

"Shut The Fuck Up EDGE !!!"

 

An extremely incomfortable silence settled upon the living room.

 

It always started the same way. Stretch would be sitting on the couch, quietly watching TV or taking a quick nap, when Edge would come sit with him in an effort to 'learn to know him better' as he had promised Red. But every time, _every time_ , Edge would find something to pick Stretch on : the lanky skeleton wasn't allowed to smoke, to be enthralled by a TV show, to simply be sitting on the couch lest he'd face some uncalled for insults. His efforts to get closer to his alternate self through the other's passion were harshly rejected too. Now, he was a pretty chill dude, and often didn't let the other's mean words get to him, but...

 

But today, Edge had found the button not to press.

 

And had hammered it alright.

 

_'HOW CAN YOU LET YOUR BROTHER DO ALL THE WORK WHILE HIS HEALTH IS SO LOW ?'_

 

Stretch had snapped. He didn't remember when was the last time he had shouted, much less shouted at someone. But Blue's health was a very touchy subject with him. He had spent all his childhood worrying about his brother getting hurt and dusted, and had only fairly recently accepted that Blue was now an adult and didn't need his constant protection. Blue just had too much energy and needed to exert himself on a daily basis. The training provided by Alphys had trumendously helped in using up the little skeleton's energy, but even that was often not enough to really tire him out. And Blue desperately needed to sleep, lest there would be dire consequences on his health. Stretch still remembered when he had found his brother passed out on the couch one morning, his health at a mere 0.2/1. After the quickest shortcut of his life to bring Blue to Undyne, the timid scientist had explained Blue's leftover magic hadn't 'rebooted' correctly during his sleep and had thus attacked Blue's own magical system. While it wouldn't have been very dangerous for a monster with a higher HP, Blue's life had been very close to ending. Stretch couldn't tell her it wasn't that Blue's magic had rebooted 'incorrectly', but that Blue hadn't slept _at all_. Guilt had swallowed those words down.

 

From this day on, Stretch had spent all his time making sure Blue would tire out completely, that he'd go to bed on time and sleep well.

 

Making sure Blue wouldn't die.

 

He had quickly realised he couldn't really do anything himself to wear his brother out. He just didn't have the stamina. Playing in the snow with Blue for even an hour would take up all his energy. So he had had to find strategies and tricks to exert his brother. That was when he became even more 'lazy' : he began smoking, and Blue had to clean the whole house almost everyday so that the smell wouldn't stay, he found new complex subjects to talk about with his brother, so that he had to go to the librarby to look up the most difficult words, he stopped doing laundry, and patiently listened to Blue's complaints upon having to enter the filthy cave that was his room, he... endured his brother's tacos, cooked with all the care in the world, but still burned to the core...

 

And it worked. Blue began to fall asleep on the couch when they were watching TV, even when Napstaton was on air, he went to bed earlier, sometimes he would ask Stretch to read him a story. Some days, he even came home after lunch for a quick nap. And most importantly, he never had another magic breakdown.

 

So Stretch was happy to have finally found the stability he had lacked so much in his youth. His brother was safe.

 

But then one day, Red and his brother Edge arrived in their universe from the strange and forgotten machine in their workshop. Used to the violent nature of their native universe, the two alternate skeletons had immediately attacked Stretch's brother, who had come to them to satiate his endless curiosity. After intense negociations, Blue and Stretch had convinced the two others that they were, in fact, safe in this world. They welcomed Red and Edge to their home and tried their best to make them comfortable, even though Edge's wariness didn't help at first. But even the violent skeleton finally relaxed and began opening a little, espcially to Blue, because who can resist such pure and genuine enthusiasm ? As for Stretch, he got very close to Red, who he shared good (or bad depending on the skeleton's point of vue) humor, nasty drinking habits and overall laziness with. He found out he had much more in common with the other version of his brother rather than his own alternate. But they were still different enough to spike his curiosity and to make him want to know more about Red.

 

It took them no more than a month to start flirting, to the point where even Blue noticed (though Edge curiously was still unaware), and two weeks later, their relationship had gotten so intimate they couldn't refute that they were dating anymore. Blue had been ecstatic upon hearing the news. Edge had only huffed.

 

Now that Stretch thought about it, it was around that time Edge began to throw insults at him for random reasons. He didn't dwell on it at first, because he was kind of used to being called names in the first place anyway, but Edge's particularly angry tone and nasty remarks cut him a bit deeper than usual. When he talked to Red about it, the other had apologised in his brother's stead, explaining that being safe wasn't something Edge was accustomed to and that he probably just didn't know how to react. He had reassured Stretch that it was only a coping mechanism, that Edge didn't dislike him or anything, that he was just a fucking stupid brat. And he had promised to talk about it to his brother, because fuck it Stretch was his boyfriend.

 

Things calmed down a bit after that, but then... Edge came back with even more insults. And this time they weren't for random reasons. It was like Edge had put a magnifying glass over Stretch's soul and had found a clear list of things that truly upset the lazy skeleton. It even seemed like the darker skeleton was testing his limits by picking on him about the most insignificant things and working his way up the list. So after attacking his smoking habit, his laziness, and everything that made Stretch the monster he was, Stretch knew soon the remarks would lean towards his most vulnerable weakpoint : Blue's health.

 

Stretch and Edge were watching TV while Blue was busy in the kitchen when Edge suggested (or rather commanded) Stretch should pick up his sock. Shrugging for the umpteenth time to such a comment, Stretch said he'd do it later. Edge didn't speak up for a long time, and that alone got Stretch to fidget anxiously on the couch. A silent Edge was never a good thing, he had come to learn. When the dark skeleton finally opened up his mouth, the remark hurt Stretch in the very core of his being :

 

"HOW CAN YOU LET YOUR BROTHER DO ALL THE WORK WHILE HIS HEALTH IS SO LOW ?"

 

This was as much as the lanky skeleton could tolerate and he barked out a full of hatred, "Shut The Fuck Up EDGE !!!". The only thing he could think of right now was punching Edge's teeth out of his mouth and put him in his place violently if must be. He felt his magic boil in his body and his marrow burn in his bones.

 

Alerted by Stretch's unusually loud snap, Blue's head perked up from the kitchen.

 

"GUYS WHAT HAPPENED ?" Blue's voice shook very lightly, but enough to betray his worry.

 

"NOTHING, JUST YOUR FUCKING BROTHER THINKS YOU SHOULD WORK HARDER BLUE." Edge answered before Stretch even had the time to open his mouth.

 

"What The Fuck Edge ?!"

 

"IF THAT'S NOT WHAT IT IS THEN WHY DON'T YOU JUST PICK UP YOUR FUCKING SOCK ?!"

 

Stretch just didn't know what to say. Why was it so important to Edge ? It was just a stupid sock ! Too enraged to try explaining himself calmly to the black clad skeleton, Stretch turned a pleading gaze to his brother, who he knew could do miracles with angry monsters. Blue seemed to have received the message and spoke softly. "Edge, please, try to chose your words more carefully, you know that I do not like insults..." When Edge only huffed, crossing his arms in front of him and turning his head to the side, Blue continued, "and Stretch... Edge is... not... entirely wrong ?"

 

what

 

"what ?"

 

Stretch thought he had heard wrong, but when he saw the look on Blue's face, a mix between shyness and remorse, his soul stopped.

 

"I-I mean ! It _is_ true that I do all the work in here and..." Blue didn't even have the time to finish his sentence that Stretch had already sat up, one hand on the doorknob, wishing nothing more than to just. go. away.

 

RIGHT. NOW.

 

He didn't know for how long he'd be able to keep the tears welling up in his eyes from spilling. He guessed it wouldn't be long, and he didn't want his brother and definitely not Edge to see him cry.

 

He opened the door in one swift swing, and found himself face to face with none other than his boyfriend, Red.

 

Red had gone for a walk to waterfall earlier and hadn't been present during the two tall skeletons' fight, and Stretch knew that. And yet... Stretch couldn't help his next words from slipping out of his mouth, going straight to his lover's face :

 

"GET THE FUCK OUT OF MY WAY"

 

Instantly regretting what he said, but unable to calm down from his furious state, Stretch harshly pushed Red to the side and quickly trecked through the snow, trying to put as much distance as possible between him and Edge, and Blue, and Red, and his house... and everything else.

 

He couldn't believe what just happened. Why did Edge... Why had Blue... He had shouted. He had shouted at Red. Fuck.

 

fuck

 

fuck

 

fuck...

 

 

"FUCK !!!"

 

 

 

\--------------------------------------------------------

 

Snow was beginning to fall on the little village of Snowdin, but Stretch was already too deep into the woods to really care. His hood was pulled up. The fragile snowflakes danced around him. Everything was calm. All was quiet. In the stillness of nature, his slow gait was the only sound resonating. His hands buried in the pockets of his orange hoodie, Stretch was walking quietly, admiring the hibernating forest. He wasn't cold.

 

He heard a bip and sounds of ungracious footsteps began following him.

 

The silent forest seemed endless. When he was young, Stretch had wondered on countless occasions if they had beautiful forests like this on the surface. Did the humans know what climate was ? Did they have seasons too ? Was it cold ? Was it hot ? Or humid like Waterfall ? His mind wandered to the many books he had read about the surface, its people, its history...

 

He slowed his gait a bit for Red to catch up to him. He didn't need to turn to know it was him : Edge didn't even make a sound when he walked and Blue was faster than him anyway.

 

Still lost in thoughts of the surface, he didn't want to talk right now. As much as he was afraid of a human falling in the Underground, he wanted nothing more than to one day go to the surface, meet humans, learn new things... stop being trapped...

 

He felt Red's tiny hand slip into his pocket and reflexively removed his left hand from it, silently wondering what his boyfriend was doing. Red gently grabbed the now free hand and held it loosely. Stretch hesitated, but finally intertwined his fingers with Red's.

 

They were quietly walking in the forest for another good ten minutes before Stretch hushed out, "red 'm sorry".

 

"'s okay stretch," Red whispered back.

 

Stretch squeezed Red's hand tightly, hoping it conveyed how sorry he was. Red squeezed back.

 

They continued walking hand in hand in the snowy forest, their footprints the only disturbance in the pristine landscape. Stretch had completely calmed down now that Red was with him. It still amazed him how soothing the shorter skeleton's presence could be, even while Red was such a powerful and dangerous monster. He just felt so safe with him.

 

Their walk lead them to the edge of the forest, where trees were fewer and the cliff towered above all of Snowdin. From there they could see everything from the entrance of the ruins to the bridge in front of Waterfall. The snow had stopped at some point during their quiet stroll and had effectively covered every top of every tree, making the forest spread like a warm blanket of wool over the land. Some of the houses in Snowdin had already turned on their lights, hundreds of flickering lights in the dark, not unlike the crystals of Waterfall. Though their warmer hues made them look like tiny suns rather than twinkling stars.

 

"hey" Red broke the silence.

 

"hmm ?"

 

"d'you remember the day we met ?"

 

Stretch didn't really have to dig in his memory to recall their first encounter. "Edge tried to kill my bro. so yeah i remem-"

 

"no no no, when we met i mean." Red clarified, though it didn't help Stretch that much. He was thankful for the quick change of subject because he didn't want to talk about Edge right now. Stretch was taking too much time to answer, so Red provided the answer himself, "i do. when we arrived in your world i felt something unsettling. it was strange, it was new. i had never felt it in my life." Stretch wondered what the other was talking about but patiently waited for Red to continue. Despite them being very close to each other, the rough skeleton still had some difficulties opening up. "the air didn't smell like dust. i didn't feel red gazes hidden in the shadows. i could hear the sounds of life in the forest. i instantly knew what it was. 'safety'".

 

The word was ushered like it would disappeared once told. It felt foreign in Red's mouth.

 

"blue came and Boss panicked and attacked him. and you came." Red's voice dropped, as if he was revealing a well-kept secret. And maybe he was, in a way. "you didn't even hesitate to put yourself between Boss and your bro. it was the first time i'd ever witnessed that much bravery. i've always protected my bro the best i could in our world, but even i never wanted to step in in a fight. even for Boss." The wind tickled Red's fluffy hood. Stretch unconciously drew closer to Red. "i'm sure every monster in my world would have thought you were out of your mind to protect a weak 1hp monster. but to me..."

 

Red lifted his head up and locked his gaze firmly with Stretch. His voice was confident and decided.

 

"...you were the strongest monster in the universe. don't let my bro get to you. don't let anyone get to you. i love you. and i'm proud to be your boyfriend."

 

Stretch smiled and hugged Red like he was the most precious treasure in the world. He bent until his head touched the other's cranium, dropping light kisses upon the top of his skull. He couldn't even say how happy Red's words made him feel. And the honesty he could feel in his boyfriend's eyes was so heart warming, especially when he knew how honesty was treated in Red's world, along with shows of happiness, curiosity, or love. Real love.

 

"thank you red. i love you too. so, so much."

 

He felt Red tense in his embrace, and like every time Stretch complimented him, the short skeleton began fidgetting with his leather coat, stuttering his words and his face glowing a beautiful crimson hue. "y-you're welcome... stretch... erm... i... hum i-i know 'm not very good with words... so errr... well..."

 

Aah it was just so cute when Red was all flustered like this. Stretch loved torturing him with praise. He couldn't help but chuckle a bit louder at his reaction, though it died quickly when he felt the other's bony hands lower from his back to his behind... He drew back so he could see Red's face and was met with a smug grin and deliciously mischievous eyes.

 

"red ? what are y-"

 

"shhh, lemme take care of you a bit more and show you how much i love you. let it go stretch."

 

Now that was something he knew how to do. Especially when the two hands stopped above his crotch and began rubbing the bone through the fabric of his cargo pants. He closed his eyes and let Red -heh- work his magic. He vaguely wondered if they were really going to have sex here, in the middle of the forest, surrounded by an endless coat of unmarred snow. Red unzipped his pants. Okay, they were totally going to have sex right here. Stretch put his hand on the back of Red skull, gently caressing him while the short skeleton was busy licking the bone, sliding his ruby tongue across the already forming magic. Arousal shot to his soul and a quiet and encouraging moan escaped his mouth.

 

When Red took hold of his orange shaft, Stretch couldn't resist and looked down, his mouth watering at the sight of his boyfriend sucking his dick. He could tell Red's motions were hurried by the way his throat swallowed his magic hungrily. He began rocking his hips back and forth and was satisfied when he saw Red's eyes shut and he felt his hands grab the back of his thighs tighter. He could only imagine what face Red would make when Stretch would penetrate him, what kind of sounds he could draw from the smaller skeleton... The mental image nearly made him tip over the edge, but he restrained himself before pushing Red back.

 

"come on red lets get rid of those annoying shorts," Stretch whispered in a hungry tone. He proceeded to remove the other's clothing but once the black shorts were discarded, he got too fascinated by the sight of a very tantalizing ruby cunt and was met with the insatiable desire to just eat Red out. Feeding off the crimson nectar was one of his favorite hobby after all.

 

Stretch took a strong hold of Red's legs and pulled them apart so he could bury his face into the other's magic. His broad tongue slided across the slickness of Red's pussy. Slick noises and loud moans echoed through the forest. Red was as spread as he could be, desperately grabbing at the snow. Stretch knew he wouldn't last long, so he began stroking himself before withdrawing from Red's wet pussy, adjusting his shaft so he could rub his dick to the other's lips. The friction was delicious and called for more.

 

"p-leeaase ssstretch... han... stop... stop teasing... i want to f-feel you ins...side... haa..."

 

That was asked so nicely...

 

Stretch slapped his dick forward, impaling the other in a broken cry of pleasure, and began setting a punishing pace. He pounded into Red's cunt until he shouted his name in bliss. He wanted the forest, Snowdin, and the whole Underground to know that he was making love to Red, that he was the one to draw out such delicious sounds from the normaly witty skeleton. He wanted Red's throat to feel so sore tomorrow he wouldn't be able to speak one word. Silent love making could wait for when there were people around them. Now he wanted Red to be vocal about it.

 

"t-tell me red ! tell me how my cock haa feels inside you ! hng..."

 

"it's sooo big !!! ah ! its hot and hard just like i love it ! i want more ! give me mo-ore ! ah ! stretch ! A-Ah !"

 

He felt Red's magic tighten around his shaft and tilted the other's pelvis so that he could press against Red's sweet spot. He found it pretty quickly and Red's voice instantly went up an octave, his body tensing during a very powerful orgasm. Red's reaction triggered Stretch's climax as well and his release spilled inside Red's magic, coloring it in a lighter tangerine hue. Stretch crushed their teeth together in an animalistic kiss, swallowing every sound the other managed to make during his peak. The taste of his precum was still present in Red's mouth.

 

Stretch gave one final thrust before collapsing on his boyfriend, not even bothering to pull his dick out of the warm nest that was Red's pussy. The magic would fade by itself soon enough anyway. They simply lied there, catching their breath together in the middle of the forest that was silent again. Stretch nuzzled his skull in Red's nape of the neck and was content with staying here with Red forever. After what felt like an eternity, Red spoke quietly.

 

"ill talk to him. make him apologise or something. i don't want you to feel bad because of what he said."

 

It took Stretch a minute to understand Red was talking about his brother and their fight. "it's okay, i know he didn't mean to be... mean."

 

"no but i don't want to let him think it's okay to be a dick to my boyfriend !" Red replied a bit more hotly. He wasn't angry but seemed hyped up. "you know what ? we're gonna tell him right now !"

 

"what ? are you... sure it's a good idea ? he might still be upset about-"

 

"i don't give a fuck about it ! i won't let him insult you anymore ! come on let's go !" And with that he grabbed Stretch and teleported them in Stretch's bedroom, right onto their shared bed.

 

It was now or never. They would clear the situation and Stretch would get his answers. Did Edge really depise him or not ? If so why ? And if not, then why was he always acting this way with him ? He really needed to know, and even if Red's method was a bit brutal, at least there would be a conclusion tonight. Right now even. The more he thought about it, the more Stretch was impatient to talk to Edge.

 

"you're right," Stretch said determinedly.

 

He took Red by the hand and hurried to the door...

 

"WAIT STRETCH WE CANT GO RIGHT NOW !!!"

 

...only to be suddenly stopped by the shorter skeleton. Surprised, he turned around. Did the other finally not want to confront his brother after all ?

 

"i forgot my shorts in the forest."

**Author's Note:**

> Man, I love honeymustard even more now. I tried adding a little headcanon I have (from time to time) about Red. Like he’s a real seducer, he likes to flirt and all, but when he’s the target of the flirting, he loses his brain fonction and begins to sputter and flushes hard. I want to do something with this one day… (I don’t see Red as tsundere, this is different : a tsundere acts like they don’t care, while Red would be very obvious about his desire to fuck with someone…)


End file.
